Powered clutch for aircraft wheel drive system

ABSTRACT

A powered clutch assembly is provided for an aircraft landing gear or other vehicle wheel drive system equipped with wheel drive motors controllable to move the aircraft or vehicle during ground travel. Electric power for the clutch assembly is transferred to clutch actuation elements by a rotary power transfer assembly mounted between stationary and rotating elements within the landing gear wheel drive system to clutch actuation elements. Actuation elements are powered to securely lock clutch rotating elements when required to improve the reliability of failsafe operation of the clutch assembly when torque should not be transferred and to unlock clutch rotating elements when torque should be transferred when the landing gear wheel drive system is used to drive the aircraft during ground travel. Power transferred from the rotary power transfer assembly may also be used to operate components associated with the aircraft drive wheel other than the powered clutch assembly.

PRIORITY CLAIM

This application claims priority from U.S. Provisional PatentApplication No. 62/197,078, filed 26 Jul. 2015, the disclosure of whichis fully incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to clutch assemblies useful invehicle wheel drive systems and specifically to a powered clutchassembly useful in an aircraft electric powered wheel drive system todrive aircraft independently of the aircraft's engines during groundoperations.

BACKGROUND OF THE INVENTION

It has been proposed to power nose and/or main aircraft landing gearwheels with electric and other drive motors to drive aircraftautonomously or independently during ground travel and move aircraftwithout operating the aircraft main engines to provide thrust or usingtow vehicles. The airline industry, moreover, is beginning toacknowledge that continuing to use an aircraft's main engines to moveaircraft during ground operations is no longer the best option and isassociated with safety issues, excess fuel use, and other challengesthat may pose significant concerns for airlines. Improvements inaircraft ground travel that avoid reliance on aircraft main engines formotive power, including the use of landing gear wheel-mounted electricand other drive motors to power aircraft ground movement, continue to besought. Control of the actuation of and transfer of the torque requiredto drive powered aircraft landing gear drive wheels, for example, mustensure that these drive wheels are driven only in a desired direction oronly during selected times and conditions when an aircraft is drivenautonomously during ground travel and that wheel drive systems are notengaged or operational at other times.

Many types of vehicle torque transferring clutch assemblies are known inthe art. U.S. Pat. No. 3,075,623 to Lund; U.S. Pat. No. 3,599,767 toSoderquist; and U.S. Pat. No. 7,661,329 to Cali et al., for example,describe clutch assemblies incorporating sprag or pawl elements that maytransmit torque between races or rotatable elements depending, in part,on their relative directions of rotation. One way vehicle clutchesdesigned to lock in one direction and allow free rotation in theopposite direction are also available, as are improved selectable oneway clutch designs, such as those described in U.S. Pat. No. 6,290,044to Burgman et al.; U.S. Pat. No. 7,980,371 to Joki; and U.S. Pat. No.8,042,670 to Bartos et al. Various other selectable clutch designs thatprovide controllable overrunning and coupling functions in automotiveautomatic transmissions, are described in U.S. Pat. No. 8,079,453 toKimes and in U.S. Patent Application Publication Nos. US2010/0252384 toEisengruber; US2011/0233026 to Pawley; and US2013/0277164 to Prout etal. While the foregoing clutch designs may function effectively totransfer torque in automotive applications, including in powered vehicledrive wheels, they are not sufficiently robust to withstand loads onaircraft landing gear structures during landing and to functioneffectively and reliably in an aircraft landing gear wheel drive systemenvironment. Moreover, these systems do not provide the kind of failsafecapability that ensures that the clutch will never be engageable duringflight, landing, takeoff, or during any other aircraft operatingcondition when operation of an aircraft landing gear wheel drive systemwould be unsafe.

A range of aircraft landing gear wheel drive systems that may be used todrive aircraft on the ground without reliance on aircraft main engineshas been proposed in the art. U.S. Pat. No. 7,445,178 to McCoskey etal.; U.S. Pat. No. 8,109,463 to Cox et al.; U.S. Pat. No. 8,684,300 toWilson et al.; and U.S. Patent Application Publication Nos. 2009/0294577to Roques et al.; 2010/0065678 to Kiyosawa; and 2010/0276535 to Charuelet al. are illustrative of various drive systems intended to moveaircraft autonomously on the ground. U.S. Pat. No. 7,469,858 to Edelson;U.S. Pat. No. 7,891,609 to Cox; U.S. Pat. No. 7,975,960 to Cox; and U.S.Pat. No. 8,109,463 to Cox et al., owned in common with the presentinvention, describe aircraft drive systems that use electric drivemotors to power aircraft wheels and move an aircraft on the groundwithout reliance on aircraft main engines or external vehicles. Whilethe drive motors described in the foregoing patents and publishedapplications may be used to move an aircraft autonomously during groundoperations, it is not suggested that torque transfer between the drivemotors and the aircraft landing gear wheels driven by the drive motorsmay be achieved by selective activation of a powered clutch assembly orsystem that reliably and selectively transfers torque to an poweredaircraft drive wheel only when safe operation of the aircraft wheeldrive system may be ensured.

A need exists, therefore, for a reliable clutch assembly with theadvantages of a selectable one—way clutch that is specifically designedto be an integral component of an aircraft powered landing gear wheeldrive system and to selectively and safely transfer torque only whenrequired to drive an aircraft drive wheel and move the aircraftautonomously on the ground and, further, that has a failsafe mechanismactivatable to ensure that the powered clutch assembly may not engagethe aircraft drive wheel to transfer torque unless the powered landinggear wheel drive system may be operated safely.

SUMMARY OF THE INVENTION

It is a primary object of the present invention, therefore, to provide areliable clutch assembly with the advantages of a selectable one—wayclutch that is specifically designed to be an integral component of anaircraft powered landing gear wheel drive system, that selectively andsafely transfers torque only when required to drive an aircraft drivewheel and move the aircraft independently or autonomously on the ground,and, further, that has a failsafe mechanism activatable to ensure thatthe powered clutch assembly may not engage the aircraft drive wheel totransfer torque unless the landing gear wheel drive system may beoperated safely.

It is another object of the present invention to provide a poweredclutch assembly for an aircraft ground travel landing gear wheel drivesystem operatively coupled to landing gear wheel drive system componentsto automatically and selectively transfer torque to wheel drive systemcomponents as required to drive the aircraft autonomously in a desireddirection during taxi.

It is an additional object of the present invention to provide a poweredclutch assembly for a wheel drive system mounted within an aircraft noseor main landing gear wheel with integrated torque-transferring drivesystem components designed to fit completely within space available inan aircraft landing gear wheel that is powered to control the transferof torque through wheel drive system components only when the aircraftmay be driven safely on a ground surface.

It is a further object of the present invention to provide an aircraftlanding gear wheel drive system with a powered clutch assembly thatincludes a clutch with selectable one-way capability controlled andpowered to reliably engage or disengage a drive motor and transfertorque through wheel drive system components selectively as required tomove the aircraft on the ground and/or to ensure that the drive motor isnot engaged when the aircraft is in flight, during landing or takeoff,and at other times when the drive motor should not be operational.

It is yet a further object of the present invention to provide apower-actuated locking clutch assembly with selective one-way capabilitythat is electrically actuatable so that the clutch assembly is reliablylocked in a desired position to selectively transfer or not transfertorque to a drive motor in an aircraft landing gear wheel drive system.

It is yet an additional object of the present invention to provide apower supply for a powered clutch assembly in an aircraft landing gearwheel drive system integral with drive wheel system structures that iscontrollable to selectively supply power to powered clutch assemblyactuation elements that may engage or disengage drive motor and drivemotor activation components to selectively transfer torque in responseto predetermined or selected aircraft operating conditions or aircraftenvironmental conditions.

It is yet another object of the present invention to provide a rotaryelectric power transfer system to transfer electric power to actuate apowered clutch assembly, as well as to transfer electric power to otherwheel-mounted components of an aircraft landing gear drive wheel or awheel drive system for a aircraft landing gear wheel.

In accordance with the aforesaid objects, the present invention providesa powered clutch assembly useful in an aircraft landing gear wheel drivesystem with powered electric or other drive wheel motors controllable tomove an aircraft independently of aircraft engines or tow vehiclesduring ground travel. The clutch assembly is powered with a source ofelectric power transferred through a rotary power transfer system thatmay be mounted with drive wheel system components within an aircraftlanding gear drive wheel. The powered clutch assembly is controllablycoupled to the aircraft wheel drive system to selectively transmittorque or not transfer torque to the wheel drive system so that theaircraft drive wheel will be driven only when the aircraft is on theground and will not be driven when the aircraft is in flight, duringlanding and takeoff, and at other times during aircraft operation whensafety or other considerations dictate that the aircraft drive systemshould not be engaged. Powered actuation elements or pins areelectrically actuated to lock clutch rotating elements when required toselectively transfer torque to drive system components only when thedrive system components should be operated to drive the aircraft. Thisarrangement also improves the reliability of failsafe operation of theclutch assembly and prevents torque transfer to the drive system whentorque should not be transferred. The rotary power transfer system,which may include a rotary transformer or the like, may transferelectric power to operate structures associated with the aircraft drivewheel other than the powered clutch assembly.

Other objects and advantages will be apparent from the followingdescription, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional schematic view of a portion of an aircraftlanding gear and a landing gear drive wheel in an aircraft landing gearwheel drive system with a powered clutch assembly that shows an electricdrive motor engaged by the clutch assembly;

FIG. 1B is a cross-sectional schematic view of a portion of an aircraftlanding gear and a landing gear drive wheel in an aircraft landing gearwheel drive system with a powered clutch assembly that shows an electricdrive motor disengaged from the clutch assembly;

FIG. 2 is a schematic perspective view of a portion of the poweredclutch assembly of the present invention in an aircraft landing geardrive wheel showing a rotary power transfer system and actuatorassembly;

FIG. 3 is a schematic front cross-sectional view of a portion of thepowered clutch assembly of the present invention in an aircraft landinggear drive wheel showing the actuator elements and torque transfercomponents of the system;

FIG. 4 is a schematic front cross-sectional view of a portion of thepowered clutch assembly of the present invention in an aircraft landinggear drive wheel showing components of the rotary power transfer systemand an actuator element;

FIG. 5 is a front view of a portion of an aircraft landing gear wheelhub and cover showing components of the powered clutch power supply andtransfer system and actuator elements;

FIG. 6A is a schematic front view of one embodiment of a clutch notchplate element useful in the powered clutch assembly of the presentinvention; and

FIG. 6B is a schematic front view of one embodiment of a clutch pocketplate element useful in the powered clutch assembly of the presentinvention

DESCRIPTION OF THE INVENTION

The benefits of being able to efficiently and safely move an aircraftindependently or autonomously during ground operations without relianceon the aircraft's main engines or external tow vehicles have beenrecognized. Actually achieving these benefits, however, has provedchallenging. Applicant's previously proposed aircraft landing gear wheelnon-engine drive motors and systems have been demonstrated toeffectively power drive wheels and move aircraft on the ground and,thus, can enable aircraft operators to achieve the advantages ofautonomous ground movement. The present invention improves thecapabilities of Applicant's original aircraft landing gear drive wheeldrive systems and expands the advantages possible when aircraft can bedriven autonomously during ground operations by controllable non-enginedrive motors and systems independently of the aircraft's main enginesand external ground vehicles. These advantages and improvements areachieved, in large part, by the design of a powered clutch assembly withan actuation system powered by a wheel-mounted rotary power transfersystem to selectively transfer or not transfer torque and controloperation of an aircraft landing gear drive system drive motor toactuate or de-actuate the drive motor, as appropriate, so that the drivemotor is actuated only when the drive system should be engaged.

Referring to the drawings, which are schematic and/or diagrammaticrepresentations and are not drawn to scale, FIGS. 1A and 1B show,respectively, schematic cross-sectional views of a portion of anaircraft landing gear wheel assembly 10, including an axle 12, andindicate the location of a strut 14 that would extend outwardly of theaxle 12 to connect landing gear wheels to the body of an aircraft (notshown). While the landing gear wheel assemblies 10 shown may be moretypical of nose wheel landing gear assemblies, either or both nose wheellanding gear assemblies or main wheel landing gear assemblies arecontemplated as locations for a powered clutch driven aircraft drivesystem in accordance with the present invention. A single landing gearwheel 16 is shown mounted for rotation on the axle 12. In a typicalaircraft nose landing gear assembly, a second wheel (not shown) wouldalso be mounted on the axle 12 on an opposite side of the strut 14 atlocation 18. Nose landing gears on some aircraft have only a singlewheel, and it is contemplated that a single wheel could be adapted toaccommodate the present powered clutch and drive wheel componentsrequired for autonomous aircraft ground movement. Larger numbers ofwheels may be mounted on multiple axles in aircraft main landing gearassemblies. A tire 20 is mounted on a tire-supporting section 22 of thewheel 16.

Although not shown in detail in FIGS. 1A and 1B, a drive motor and drivemotor activating system, represented by the block 24, may be mountedcompletely within the wheel 16, within in an interior volume 26 definedby the configuration of the wheel wall structures. In an electric drivewheel drive system, the drive motor may be an electric drive motor. Inanother drive system, for example a hydraulic or pneumatic drive system,the drive motor may be a hydraulic drive motor system or pneumatic drivemotor system, or any other suitable type of drive motor that may beconfigured to fit within the wheel volume 26. The powered clutchassembly described herein may be adapted or modified to function asdescribed herein with different types of drive motors and drive systems.A preferred electric drive motor may include at least a rotor and astator and may be capable of operating at speeds that will generatesufficient torque to drive aircraft of a range of different sizes duringground travel. A range of electric motor designs capable of high torqueoperation across a desired speed range that can drive an aircraft wheelto move an aircraft on the ground and function as described herein arecontemplated to be within the scope of the present invention. Forexample, without limitation, a high phase order electric motor of thekind described in commonly owned U.S. Pat. Nos. 6,657,334; 6,838,791;and 7,116,019, the disclosures of the aforementioned patents being fullyincorporated herein by reference, may be effectively used with thepresent invention. Other functionally equivalent electric motors mayalso be used.

A drive motor activating system (not shown) useful with an electricdrive motor and the powered clutch assembly of the present invention maybe a gear system that includes, for example without limitation, anarrangement of planetary and sun gears in torque transfer relationshipwith the powered clutch of the present invention, a roller tractiondrive system, or any other suitable drive motor activating system thatmay operate with a powered clutch assembly as described herein whentorque is transferred to the drive motor activating system to activateor de-activate a drive motor in an aircraft landing gear drive wheel. Asnoted above, both the drive motor and the drive motor activating systemshould be sized to fit within the volume 26 defined within the wheel 16.

A powered clutch assembly 28 in accordance with the present inventionmay be activated automatically or manually to selectively transfertorque through the drive motor activating system to the drive motor toengage the drive motor to move an aircraft drive wheel to drive theaircraft in a desired ground direction at a desired speed or a torqueassociated with a desired speed or, when appropriate, to disengage thedrive motor so that it is unable to drive the aircraft drive wheel. Thedrive motor should only be engaged by the powered clutch assembly whenthe aircraft is actually on the ground, such as after landing and priorto takeoff, and when the aircraft is traveling at a desired speed duringground travel. Engagement and disengagement of the drive motor by thepowered clutch assembly 28 could be targeted, for example, to the speedof the aircraft wheel 16 and/or to speeds of drive wheel systemcomponents, for example the speed of the drive motor, the speed of adrive motor rotor, and/or the speed of the drive motor activating systemrotating components. Drive motor engagement and disengagement may alsobe targeted to predetermined environmental or other conditions. Aselectable one-way clutch that can be selectively engaged in a forwardand or a reverse rotational direction and that has a failsafeoverrunning capability may be adapted for use in the powered clutchassembly of the present invention.

The powered clutch assembly 28 may advantageously be located within thedefined volume 26 within the wheel 16 in torque transfer communicationwith the drive motor and the drive motor activating system interiorly ofa wheel section 30 adjacent to the axle 12, as shown in the drawings.However, other locations within an aircraft wheel may be moreappropriate in some wheel drive system configurations and are alsocontemplated to be within the scope of the present invention. Power forthe powered clutch assembly of the present invention may be transferredby a rotary power transfer element that may be connected to a supply ofaircraft electric power, such as a rotary transformer 32 or anotherrotary power transfer element. This arrangement may be seen more clearlyin FIGS. 2-4 and is discussed in greater detail below.

Although a range of different types of clutches capable of automaticallyand selectively transferring torque is described in the art, they havebeen designed to drive automotive automatic transmissions, which presentvery different design and operating conditions from those presented inan aircraft wheel drive system intended to move a range of differentsizes and types of aircraft on ground surfaces. The available clutchdesigns may not have the robustness and reliability required to functionto effectively transfer or not transfer torque as required in anaircraft landing gear wheel drive system environment.

One type of clutch assembly that may be adapted for use in the poweredclutch driven aircraft wheel drive system described herein is a clutchassembly that incorporates features of both a one-way clutch and aselectable or controlled one-way clutch in a single clutch assembly thatmay be engaged selectively in one or both directions and has a failsafeoverrunning capability to ensure that the clutch may not engage thedrive system to drive the aircraft wheel during flight, landing,takeoff, or during other situations when operation of the drive systemwould not be safe. Commonly owned co-pending application Ser. No.14/611,100, filed 30 Jan. 2015, the disclosure of which is fullyincorporated herein by reference, describes a selectable one-way clutchthat may be adapted for use with the present invention as describedbelow. The locking elements currently provided for selectable one-wayclutches may include a number of circumferentially spaced rockers,struts, or similar movable locking elements on one clutch element thatengage corresponding windows or pockets in another clutch element. Thelocking elements may be configured to selectively hold torque in aselected forward and/or reverse rotational direction to establishdifferent clutch operating modes. Such clutches, particularly thosedisclosed in U.S. Pat. No. 8,079,453 to Kimes and in U.S. PatentApplication Publication Nos. US2010/0252384 to Eisengruber;US2011/0233026 to Pawley; and US2013/0277164 to Prout et al. cited inthe Background of the Invention above, have been proposed for use inautomobiles. The disclosures of these patents and published patentapplications are incorporated herein by reference. Automobile drivesystems, however, are not subject to the loads and stresses typicallyencountered in an aircraft landing gear wheel drive system, and theaforementioned locking elements may not reliably allow or prevent torquetransfer in an aircraft landing gear wheel application, particularlywhen subjected to the vibrations and shocks that accompany aircraftlandings. The powered clutch assembly of the present invention improvesthis type of clutch system to overcome these and other challenges.

FIGS. 2-4 illustrate the powered clutch driven aircraft landing gearwheel drive system of the present invention in more detail. Portions ofthe landing gear wheel and other landing gear structures shown anddescribed in connection with FIGS. 1A and 1B are identified with samereference numbers used in FIGS. 1A and 1B. In FIG. 2, the drive systemappears schematically in cross-section from a perspective that shows thewheel 16 supported on the axle 12 and the drive system components withinthe volume 26 defined by the wheel 16. FIGS. 3 and 4 illustrateschematic front cross-sectional views of an aircraft landing gear wheel16 with the powered clutch assembly and the wheel drive system of thepowered clutch driven aircraft landing gear wheel drive system of thepresent invention as it appears on opposite sides of the axle 12.

The powered clutch assembly 28 of the present invention is powered byelectric power that may be transferred to the clutch assembly from anaircraft supply of electric power by a rotary power transfer assembly,such as the rotary transformer 32. The rotary transformer 32 embodimentshown may include a stationary element 34 and a rotary element 36. Thestationary element 34 may be attached to a stationary or non-rotatingsection 38 of the wheel 16, which may then be attached to a torque takeout structure 40 that may preferably be in an inboard location of thelanding gear. The rotary element 36 rotates or spins with the wheel 16to transfer power for clutch actuation through a wire 42 that may bepositioned in a trench 44 in the wheel section 30. The wire 42preferably exits the wheel through a channel 46 to connect with one ormore clutch actuator motors 48 on an exterior face of the wheel 16,which may be seen more clearly in FIG. 5. Electric power transfer topower clutch actuation elements may also be produced by and/or obtainedfrom other rotary power transfer elements or assemblies, for examplewithout limitation, slip rings and the like. Any rotating power transfercomponent connected between a stationary landing gear component and alanding gear wheel rotating component may be used in a power transfersystem to transfer electric power to clutch actuation elements asdescribed herein and is contemplated to be within the scope of thepresent invention.

One embodiment of a drive motor and drive motor activating system isshown in FIGS. 2-4. This drive motor and drive motor activating systemmay be enclosed within a housing 50 that may be secured to the wheelnon-rotating or static wall 38. A preferred electric drive motor 24 mayhave an arrangement of one or more stators 52 and rotors 54 as shown inFIGS. 3 and 4, although electric drive motors with other configurationsand arrangements of stationary stator elements and rotating rotorelements are contemplated to be within the scope of the presentinvention. A drive motor activation system 56, which, as indicatedabove, may be a system of gearing or a roller traction drive system, orany other suitable drive motor activating system, is located within thehousing 50 and may be positioned to activate the drive motor 24 andtransfer torque as required to operate the drive motor and drive theaircraft wheel on the ground. Electric power for an electric drivemotor, such as the drive motor 24, may also be supplied by a wireharness or the like (not shown) connected to a supply of electric power,such as the aircraft's auxiliary power unit, on the aircraft.

The powered clutch assembly 28, which may be connected to the drivemotor activation system 56 and the drive motor 24, includes at least apocket plate 58 and a notch plate 60, which are shown in front view inFIGS. 6A and 6B. The pocket plate 58 and structures mounted on thepocket plate may rotate with the wheel 16, while the notch plate may beattached to the drive motor activation system 56. A retaining ring 59may be provided to hold the pocket plate 58 and notch plate 60 indesired relative positions. A spline 61 may additionally be provided onthe wheel housing 50 or other wheel structure adjacent to the clutchassembly to engage a correspondingly configured surface on the pocketplate 58 to pass torque from the pocket plate to the wheel, as shown inFIG. 2, when the powered clutch assembly 28 is engaged to transfertorque. Alternatively, any functionally equivalent mechanical lockingelement that could be positioned in selective meshing engagement betweenthe powered clutch assembly 28 and other wheel torque transferstructures may be used in place of a spline. A range of mechanicalconnection elements, including without limitation, keyed elements, lockrings, and the like, may be used to transfer torque from the clutchassembly pocket plate 58 to the wheel housing 50 or other wheelstructure.

One available clutch assembly, referred to above and intended forautomotive and like vehicle applications, uses an arrangement of apocket plate, usually with a number of circumferentially spaced springbiased struts or locking elements that pivot into and out of engagementwith corresponding receptacles or notches on a notch plate to prevent orallow torque transmission in a selected rotational direction. As notedabove, while this arrangement may function effectively in an automotiveenvironment, the spring biased locking elements may not be sufficientlyrobust to withstand the stresses and forces to which aircraft landinggears and landing gear wheels are subjected, particularly duringlanding, to reliably selectively control torque transfer as required toensure engagement and activation of an aircraft drive system, such asthat described and shown herein, only when such engagement or activationwould be safe. Such a clutch arrangement may not reliably preventengagement and activation to transfer or not transfer torque when theaircraft drive system should not be activated or engaged, including whenthe aircraft is in flight and during landing and takeoff, as well as atany other time when operation of the aircraft landing gear drive wheeldrive system could adversely affect safe operation of the aircraft. Thepowered clutch assembly of the present invention has been specificallydesigned with components that function effectively in an aircraftlanding gear drive wheel to reliably and controllably transfer torqueonly when the aircraft drive wheel system should be activated orengaged.

As described above, the rotary transformer 32, or other rotary powertransfer element, which may connect the stationary wheel wall 38 oranother stationary landing gear structure to a rotating landing gearwheel structure, transfers power from the aircraft source of electricpower (not shown), typically through wires or the like, to the clutchassembly components and/or other wheel components to be powered. Thispower may be transferred to one or more clutch actuator motors 48through wires, like the wire 42 shown in FIGS. 2 and 4, thatelectrically connect the rotary transformer 32 with one or more clutchactuator motors 48 to transfer power to the clutch actuator motors 48.The one or more clutch actuator motors may drive a ring gear 62 that maybe exterior to the wheel 16 outboard exterior face 17. The ring gear 62may be concentric with the wheel hub 64 and located radially outwardlyof the wheel hub 64 a distance that accommodates actuation elements 66located as described below. A preferred embodiment of a clutch actuatormotor is sized to fit outboard of the wheel 16 as shown in the drawings.The clutch actuator motor may be small in size because the onlyresistance that may be encountered by the motor is air resistance as thewheel 16 rotates. Two clutch actuator motors 48 located in diametricallyopposed positions outwardly of a drive wheel hub 64 are shown in FIG. 5.Other numbers and arrangements of clutch actuator motors may also beused to power a clutch assembly on a drive wheel. Although not shown, itis contemplated that a protective wheel hub cover may be positioned overthe wheel 16 outboard exterior face 17. Such wheel hub covers areavailable for use on aircraft wheels.

The powered clutch 28 of the present invention employs a combination ofa pocket plate 58 and a notch plate 60 that may be activated by alocking arrangement that employs actuation elements or actuation pins 66spaced circumferentially with respect to the wheel hub 64. Eachactuation element 66 may be formed with a head 68 that has a largerdiameter than the remainder of the actuation element to have a“hammerhead” configuration. The actuation elements 66 may be mounted inthe wheel as shown in FIGS. 1A, 1B, and 3 to extend from the wheel 16outboard exterior face 17 through the wheel so that the head 68 engagesthe clutch 28. The actuation elements are activated by power transferredfrom the rotary transformer, or a slip ring or like rotary powertransfer structure, to the clutch actuator motors 48 and the ring gear62 from an outboard side of the wheel to lock both the pocket plate 60and the notch plate 58 when the actuation elements 66 are powered anddriven in an inboard direction to engage both clutch plates. Thisapproach eliminates the need for the struts typically used to lock apocket plate and a notch plate in this type of clutch. The foregoingarrangement, moreover, is significantly more reliable in an aircraftlanding gear environment than in an automotive environment and is ableto withstand shocks and vibration that accompany landing with morereliable failure modes. Four actuation elements 66 are shown spacedequidistantly radially outwardly of the wheel hub 64 in FIGS. 5 and 6B.The configuration of the “hammerhead” end 68 of the actuation elements66 is shown in cross-section on the pocket plate 58 in FIG. 6B.Correspondingly shaped receptacles 70 in the notch plate 60 maybeprovided to receive the “hammerhead” end 68 when the actuation pins 66are powered by the clutch actuation motors and driven into engagementwith the notch plate to engage the drive motor activation system 56 andthe drive motor 51. The position of one of the actuation elements 66when the drive motor and drive motor activation system are engaged isshown in FIG. 1A. Both the pocket plate 58 and the notch plate 60 arelocked together in a manner that may withstand vibrations, shocks, andother stresses which may be exerted on aircraft landing gear componentswhile effectively transferring torque through the wheel drive system tomove the aircraft in forward or reverse on the ground.

The disengaged position of the actuation element 66, in which the pocketplate 58 and the notch plate 60 are not locked together and torque isnot transferred through the wheel drive system components is shown inFIG. 1B. Power is not transferred by the rotary transformer 32 throughthe clutch actuator motors 48 and ring gear 62 to the clutch actuationelements 66 in this disengaged condition. Control of the rotarytransformer to stop the transfer of power is preferably automatic, butmay also be manual. It is contemplated that suitable automatic controlelectronics and processors will be provided to automatically controlpower transfer from the rotary transformer 38 to the clutch actuatormotors 48. It is also contemplated that a suitable pilot-activatedmanual control element in communication with the rotary transformercontrol electronics may be provided in an aircraft's cockpit controlarray.

Providing four spaced actuation elements 66 associated with the pocketplate 58 and four receptacles 70 in the notch plate 60 as shown mayfacilitate alignment of the actuation elements 66, pocket plate 58, andnotch plate 60 when the actuation elements are powered to lock thepocket plate and notch plate and engage the drive motor activationsystem 56 and the drive motor 24. Backlash is not an issue with thepowered clutch arrangement described herein, and alignment of thepowered clutch components may be achieved without sensors. The use ofone or more “dummy” actuation elements that are not powered may besuitable in some powered clutch applications and is contemplated to bewithin the scope of the present invention. Additionally, transferringpower to only one of the clutch actuator motors or to a number less thanthe full complement of clutch actuation motors may be more effective insome applications, and this is also contemplated to be within the scopeof the present invention.

The transfer of electric power to rotating aircraft landing gearstructures by a rotary transformer connected to a landing gear wheelstationary structure may be used for purposes other than powering clutchactuation elements as described above. Power could be transferred to anyother rotating aircraft wheel components that require a source ofelectric power, for example without limitation, to sensors and lights.Control electronics may be adapted to send power to several differentwheel components in addition to, or instead of, clutch actuatingelements. The structure of the rotary transformer could also be modifiedto transfer power to more than one location. As noted above, the rotarytransformer could be replace by a slip ring or like rotary powertransfer element. Other variations of the rotary transformer powertransfer system of the present invention are also contemplated be withinits scope.

It is preferred that the components of the powered clutch assembly ofthe present invention be designed to withstand high torque loads,preferably torque loads in excess of a determined maximum torque loadfor an aircraft drive wheel drive system and made of materials suitablefor effective long term operation in the environmental conditions likelyto be encountered in aircraft landing gear wheels.

While the rotary power transfer system described herein may be mostadvantageously used in aircraft landing gear drive wheels, this systemmay also be used to transfer electric power in other vehicles that aredriven by powered drive wheels and have drive systems for the powereddrive wheels with electric motors that are activated by clutch-actuateddrive systems. Other applications of this rotary power transfer systemare also contemplated to be within the scope of the present invention.

While the present invention has been described with respect to preferredembodiments, this is not intended to be limiting, and other equivalentarrangements and structures that perform the required functions arecontemplated to be within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The powered clutch assembly and the rotary transformer power generationand transfer system of the present invention will find their primaryapplicability in aircraft landing gear wheel drive systems to reliablyand effectively transfer torque and power to components of aircraftlanding gear wheel drive systems as aircraft are driven autonomouslywithout aircraft engines or tow vehicles during ground travel by theoperation of the landing gear wheel drive systems.

The invention claimed is:
 1. A powered clutch assembly electricallyactuatable to control operation of a drive motor in an aircraft landinggear wheel drive system to drive the aircraft only when the aircraftshould be driven during taxi on a ground surface, comprising: a. anaircraft landing gear wheel drive assembly mounted completely within aninterior volume defined by wheel wall structures of an aircraft landinggear wheel, said wheel drive assembly comprising at least a drive motor,a drive motor activating system, and an electrically actuatable poweredclutch assembly located within said defined interior volume in torquetransfer engagement and disengagement with said drive motor; b. saidelectrically actuatable powered clutch assembly being in selectivetorque transfer contact with said drive motor and comprising at leastone or more clutch actuator motors, a ring gear driven by said one ormore clutch actuator motors, a pair of clutch plates, and poweredactuation elements driven by said ring gear to engage and lock or torelease said pair of clutch plates; and c. an electric power supplysystem for said electrically actuatable powered clutch assemblycomprising at least a source of electric power on said aircraft and arotary power transfer element connecting a stationary landing gear wheelstructure to a rotating landing gear wheel structure, said rotary powertransfer element connecting said source of electric power to said one ormore clutch actuator motors and to said powered actuation elements insaid electrically actuatable clutch assembly.
 2. The assembly of claim1, wherein said rotary power transfer element comprises a rotarytransformer comprising a stationary portion attached to a static portionof said aircraft landing gear wheel and a rotating portion that rotateswhen said aircraft landing gear wheel rotates.
 3. The assembly of claim1, wherein said one or more clutch actuator motors are mounted on anoutboard face of said aircraft landing gear wheel in driving contactwith said ring gear, and one or more wires connect said one or moreactuator motors to said rotary power transfer element.
 4. The assemblyof claim 1, wherein each of said powered actuation elements comprises anactuation pin with a uniformly cylindrical body section integrallyformed with a hammer-shaped actuating head section configured to engageand lock both said clutch plates.
 5. The assembly of claim 4, whereinsaid powered actuation elements are positioned with the cylindrical bodysection outboard of said wheel to receive electric power from said ringgear in contact with said one or more clutch actuator motors and withthe hammer-shaped actuating head section in or out of engaging andlocking contact with both said clutch plates.
 6. The assembly of claim5, wherein each of said pair of clutch plates comprise powered actuationelement engagement and locking receptacles for each said poweredactuation element having a cross-sectional configuration correspondingto a cross-sectional configuration of said hammer-shaped actuating headsection.
 7. The assembly of claim 1, wherein a housing section of saidaircraft landing gear wheel comprises a mechanical locking elementpositioned in selective meshing engagement with one of said pair ofclutch plates.
 8. The assembly of claim 7, wherein said mechanicallocking element comprises a spline element, a key element, or a lockring element.
 9. The assembly of claim 1, wherein said drive motoractivation system comprises a gear system or a roller traction drivesystem in torque transfer contact with said drive motor.
 10. Theassembly of claim 1, further comprising automatic or manual controlmeans for controlling and directing a supply of electric power from saidsource of electric power on said aircraft to said rotary power transferelement.
 11. The assembly of claim 3, further comprising four spacedclutch actuator motors mounted on said outboard face of said aircraftlanding gear wheel and connected by said one or more wires to saidrotary power transfer element in driving contact with said ring gear.12. A method for controlling actuation of a powered clutch assemblyelectrically actuatable to control operation of a drive motor in anaircraft landing gear wheel drive system to drive the aircraft only whenthe aircraft should be driven during taxi on a ground surface,comprising: a. providing an aircraft landing gear wheel drive assemblycomprising at least a drive motor, a drive motor activating system, andan electrically actuatable clutch assembly in selective torque transfercontact with the drive motor and mounting the landing gear wheel driveassembly completely within an interior volume defined by wheel wallstructures of an aircraft landing gear wheel; b. providing anelectrically actuatable powered clutch assembly comprising at least oneor more clutch actuator motors, a ring gear driven by the one or moreclutch actuator motors, a pair of clutch plates, and powered actuationelements driven by the ring gear to selectively engage and lock the pairof clutch plates and an electric power supply system to direct power tothe clutch actuator motors and the powered actuation elements from asource of electric power on the aircraft through a rotary power transferelement; c. while the aircraft is driven during taxi on a groundsurface, directing electric power from the aircraft source of electricpower through the rotary power transfer element to the one or moreclutch actuator motors, and transferring power from the clutch actuatormotors to the powered actuation elements and causing the poweredactuation elements to move in an inboard direction to engage and lockthe pair of clutch plates and the powered clutch assembly into torquetransfer contact with the drive motor; and d. when the aircraft shouldnot be driven during taxi on the ground surface or the drive motorshould not be operated, automatically or manually stopping transfer ofelectric power to the powered actuation elements, causing the poweredactuation elements to be depowered and to move in an outboard directionout of engagement with the clutch plates, and releasing the pair ofclutch plates and the powered clutch assembly from torque transfercontact with the drive motor.
 13. The method of claim 12, furthercomprising providing a plurality of clutch actuator motors and aplurality of powered actuation elements in actuating contact with theclutch actuating motors, transferring electric power to the plurality ofclutch actuator motors in actuating contact with the plurality ofpowered actuation elements, and driving the plurality of poweredactuation elements from the outboard to the inboard direction intolocking engagement with the pair of clutch plates and the clutchassembly into torque transfer contact with the drive motor.
 14. Themethod of claim 12, further comprising transferring electric power fromthe supply of electric power through the rotary power transfer elementto components other than the clutch assembly comprising at least sensorsand lights mounted on the aircraft landing gear wheel that requireelectric power for operation.